If the Government have shown judgment and foresight upon this point, we cannot say as much for their inexcusable neglect to provide for the security of this enormous establishment, which contains within its walls not only the principal depôt of warlike stores in the island, but also the means of producing them. We do not believe that our neighbours are going to sail up the Thames quite as easily as the Dutch did, or that any foreign army marching from Dover could destroy the Arsenal on its way to the capital without our having ample notice of their approach. Nevertheless we cannot think that the sole Arsenal of England, placed as it is in a very accessible part of the island, should be left entirely without the means of defence. The place itself could not be fortified, as it is commanded by the heights of Shooter's Hill; but the neighbourhood is admirably adapted for the purpose. In the opinion of military engineers, it would not be necessary even to erect the requisite works until the moment their services were required. Half a dozen earth batteries, mounted with heavy guns, would command all the land approaches; and a few flats, posted so as to sweep the reaches of the river, would effectually prevent the approach of any hostile force by water. The scheme of these batteries should, however, be settled beforehand in all their details, so that in the moment of danger they could be completed almost in the presence of the enemy, in case an invader should give the Channel Fleet the slip some misty morning, and succeed in making good his footing upon our shores. SHIPWRECKS.